Well for those who believe that equality for gay Americans is the civil rights struggle of our time. This is a day on par with the emancipation proclamation women marching the polls for the first time. Of course there are still plenty who disagree with the supreme court's decision to overturn the defense of marriage act the -- was really at the state level. Despite the rulings almost two thirds of same sex couples still live in places where they cannot legally wed. So what happened today and where does America go from here here's my Nightline co anchor and are mad at scotus. Terry Moran. -- -- -- -- -- -- It was me it was gay day at the Supreme Court this morning with the repercussions ripped across the. Okay. The justices struck down the federal defense of marriage act or don't know -- And -- California's proposition eight which banned same sex marriage back to a lower court basically legalizing gay marriage. In America's most populous state. And for the -- -- challenge the California law it was a day of triumph in the long pent up emotion today's a good day. Today finally get to look. At the -- but I love. -- finally say. What you please and very human. So you just got engaged over here -- I thought holly Gagne Philadelphia that was our that was the most public proposal -- a real and I never said yes on the microphone yeah it is the end of this year on the record brother I could -- -- Word of the decision spread so quickly that President Obama spoke to the other California couple on his way to Africa a moment captured on -- -- yeah. You've talked to the president today -- We did we talk to the president call from airports want to congratulate all of us. -- is that look. I. I have to say I I was a little shaky at that moment I'm hearing his voice and then picturing him on the day and this state of the union and in his inaugural speech where he. -- our highs today out of Selma. And Seneca falls and feeling like he recognize that this battle is a good battle for the whole country and he wants to be on the winning side. And he adds and he and I we all are -- -- -- -- I'm positive we'll. David Boies who represented these plaintiffs in the prop -- case the public this -- Particularly in its -- the most rewarding things that lie on my colleague Reynolds and government involvement. Because it has effected. People's lives and live in -- fundamental way yeah and because. It has brought this society. Closer to the ideals on the wrong. -- -- prop -- case affect millions in California the other case decided today overturning the defense of marriage act. Is far more sweeping and it shows dramatically how much this country has changed in the last seventeen years. Don't always passed in 1996 -- -- defined marriage under federal law as the union of one man one woman thus denying legally married gay couples. Equal treatment under federal law. The senate debate was filled with dire predictions and -- year deportable and our community is the legal recognition. Of same sex marriage would being social engineering. Beyond anything and the American experience what took thousands of years. To build. And being dismantled. In a generation but in just the last eight months six states have recognized gay marriages and politicians who want to oppose it are now supporting marriage equality. Today the court struck down -- a five to four led by justice Anthony Kennedy who declared in -- bringing terms. That the law is unconstitutional. Because it demeans the couple humiliate tens of thousands of children. Now being raised by gay couples and serves no legitimate purpose and violates the constitution's guarantee. Of the quality but Japanese grand opinion drew a blistering dissent from justice Antonin Scalia who called today's ruling -- jaw dropping. And accused Kennedy in a liberal justices of declaring anyone opposed to same sex marriage an enemy of human decency. Hood minds -- exhausted -- love my arrives. Make -- community. But for Edie Windsor the 84 year old -- in the -- a case what mattered was that she -- -- and she wept when she heard the news this morning. Her case -- rose from the love of her life Thea -- they spent 44 years together in New York City finally got married in 2007 in Canada. But then after -- died in 2009. -- who lives on a fixed income was suddenly hit with 363000. Dollars in state taxes taxes no straight widow would have to pay. She sued the federal government for discrimination. I spoke to were soon after the court agreed to hear her case. We've been married to anybody would want OK gay or straight who had a wonderful life together. Today my colleague Diane Sawyer spoke to her after the ruling came down when you heard the news. What did you do cry. Chris -- OK and the room was full of people. So that was done screaming and crying at the same time I heard you say of yourself. This old lady flourished. Yeah -- support of the community who -- easy. The what happened is I think -- -- who heads have had no one he would avoid the possible effects of of that move would be attacked. -- -- -- -- And think oh wow she's good -- -- fed her her campaign and they are they treating me make him if someone different. Four hours after the ruling the Supreme Court it was a scene of jubilation the Internet almost exploded with the news Google -- the gay rainbow symbol when you typed in certain searches. Early tweets couldn't suppress the excitement. From Leonardo DiCaprio historic day well done scotus Ben Affleck big news from the Supreme Court goodbye don't -- prop eight. Hello equality. Perez Hilton keep calm and marry on. -- -- Don't wanna Traficant stereotypes but let's be real I'm gonna -- gay wedding since San Francisco this celebration started early in the morning and the emotions. Overwhelming ABC Cecilia Vega talked to a couple who had just proposed. When the word came down. -- thank you have very exciting is a great day for democracy. Great great. To be endless sea of people for whom -- matter so much it's very excited and it's very. It's emotional it's -- military housing. But for millions of Americans who oppose gay marriage and cherished traditional marriage today was a dark day. It's a sad day when unelected judges. That changed the definition of marriage in in in turn their backs on the will of voters across the country there was this sense that something big had happened. Meaning of American equality that -- bedrock principles today's extended once again renewed. When you get prohibited from. We have denied the right. Well done and that's what. Doubting yourself if you feel this my country in my state really want to -- discrimination against it just because of the personnel. We're like everybody else. We hope that everyone -- the person that they want to -- and has the right to do that because that's for a country that. -- -- For Nightline I'm Terry Moran moved. And it.

This transcript has been automatically generated and may not be 100% accurate.

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